Hot air furnace



Aug. 4, I942. cs. A. TU CK 2,292,180

HOT AIR FURNACE Filed March 25, 1940 2 Sheets-Sheet l 722/ 3 /5 33 X /rw m km M /m /r\\ 32 I IS INVENTOR 660/99 A7. Tuck ATTORNEY 1942- 2 G. A. TUCK 2,292,180

HOT AIR FURNACE Filed March 25, 1940 2 Sheets-Sheet 2 INVENTOR George 4. Tuck ATTORN EY Patented Aug. 4, 1942 UNITED STATES PATENT OFFICE 10 Claims.

This application is a continuation in part of my copending application, Serial No. 288,728, filed August 7, 1939, for Hot air furnace.

It is an object of the invention to provide an improved compact furnace of the above character making use of a series of heat transfer sections which are each provided with an individual burner.

Another object of the invention is to provide a hot air heating furnace of the character referred to which gives a relatively high capacity for a given area of heat transferring surface and gives a maximum area of heat transferring surface within the space occupied.

Another object of the invention is to provide a hot air heating furnace of the above character in which the group of heat transfer sections have baffled passages therein for insuring proper heat transfer distribution.

Further objects of the invention will appear from the following description, in which the preferred embodiment of the invention has been set forth in detail in conjunction with the accompanying drawings.

In the drawings:

Fig. 1 is a side elevational view, in cross-section,

illustrating a furnace incorporating the present invention.

Fig. 2 is a vertical cross-sectional view taken in a plane indicated by the line 2-2 of Fig. 1.

Fig. 3 is a cross-sectional detail taken in a plane indicated by the line 3--3 of Fig. 2.

Fig. 4 is a cross-sectional detail taken in a plane indicated by the line 4-4 of Fig. 2.

Fig, 5 is a detailed sectional View illustrating a modified form of the invention.

The furnace disclosed herein is of the type making use of a plurality of heat transfer sections formed of metal walls, and through which hot products of combustion are caused to flow in a desirable manner from a novel form of combustion chamber. Communication from a common control chamber into the heat transfer sections is established through novel means and the control of the flow of combustion products from the heat transfer sections to the flue is also established by novel means so as to insure a properly balanced and controlled flow of products of combustion.

The furnace as illustrated in the drawings includes a, housing or casing l0 provided with cold air inlets II at one side and at the bottom of the casing, and with a hot air outlet l2 at the top of the housing. This outlet may connect with hot air distribution conduits. The housing itself is of a conventional construction and is formed of sheet metal walls, which are suitably joined as by welding, and mounted on a suitable base M.

The furnace is provided with a control chamber l6, formed of sheet metal walls, and which is shown located at the back side of the housing and approximately mid-way of its height. A plurality of gas burners I1 is associated with the control chamber l6, and these burners each comprises a portion Ila within chamber 16, and a portion ll'b extended within a heat transfer unit l8.

The heat transfer sections as shown in Figs. 1 to 3 consist of pressed sheet metal side walls 2! having their edges welded or otherwise suitably joined together as indicated at 22. At the lower left-hand corner of the heat transfer sections as shown in Fig, 2 they are cut away to engage the control chamber It and ma be joined thereto as by welding at 23, to provide an air tight junction.

It will be seen that the control chamber and the heat transfer sections being rigidly secured together can be supported in the housing as a unit, as by welding of the control chamber to the housing wall at 24, and by a suitable standard 26 supporting the opposite edges of the heat transfer units IS.

The furnace is provided with flue connections in the form of tube sections 3| and 32 suitably secured in apertured walls of the housing and extending into and being welded to the heat transfer sections l8, The walls of adjacent heat transfer sections are connected by pipe section 33, also secured thereto as by welding. In order to provide controlled communication between the flue pipes and the interiors of each of the heat transfer sections IS, a replaceable pipe section 36 is extended therethrough and is provided with a longitudinal slot 31 of predetermined width.

In order to provide a proper controlled flow of the heated combustion products, baflle means are provided in the heat transfer sections to divert and distribute the flow of gas. For this purpose the sheet metal side Walls 2| of each heat transfer section are provided with formed depressions 4|, which are contoured substan tially U-shaped (as viewed in Fig. 2) with the open end of the U facing the flue outlet. Because of the bafiiing provided by the meeting of two opposed inwardly formed depressions M, the hot combustion products travel outwardly through the fixed orifices lla (Figure 3), and then over the ends of the baffle, as shown by the arrows in Figure 2 before they can reach the flue outlet, Each heat transfer section is also provided with a baffle plate 40 which in the arrangement illustrated, extends vertically below the axis of the pipe sections 3|, 32 and 33, to the depressions 4|. These baflies divide the flow of gases into two streams, thus making it possible by proper angular setting of pipe 36, to insure equalized flow of gases over the ends of the depressions 4 I.

In order to direct currents of air over the heat transfer sections, a blower 42 is shown in the lower part of the housing below the partition 43. The inlet of this blower connects with the cold air intake H of the housing. The discharge opening 64 of the blower d2 directs cold air against the two sets of divergent baffles 45 and 47, which causes a uniform flow of the air over and around the various heat transfer sections. Where lateral dimensioning is not important the blower can be located at one side with the air stream flowing laterally between and around the heat transfer sections.

The burners ll are connected to a gas supply pipe or pipes 48, and both portions Ma and l8b are provided with openings or slots 45a and 49. The main flame of each burner is formed by the portion Nb and is within its associated heat transfer section [8, rather than in a common chamber as with prior conventional furnace constructions. The flame supported by burner portions Ila is primarily for the purpose of carrying flame to all of the burners from a single pilot light 59.

The furnace described above has a high capacity for a given overall size. Heat is efficiently distributed to the walls of the heat transfer sections and to the surrounding currents of air. In effect each heat transfer unit is a furnace in itself, since it is provided with a burner and is not dependent upon an additional combustion chamber for receiving hot gases. The control chamber serves as a convenient space to receive the connections to the burners, the pilot burner, and the various control elements for the pilot and main burners. In addition air admitted to this chamber through its front closure or door serves to support combustion.

The use of replaceable pipe section 36 in the flue conduit allows for control of the Width of the slot 31 to be employed in the various installations to accommodate different draft conditions imposed by chimney construction and location, and also to insure proper operation under different atmospheric conditions, for example, those found in low and high altitudes. This arrangement cooperates with the fixed orifices a id to insure optimum gas flow distribution through the heat exchange sections, without impairment of capacity under certain operating conditions. Also, it provides a construction requiring only one simple change, namely the width of slot 3?, to properly adapt the furnace to given operating conditions.

The control of the burners can be such that for medium or lower heat, certain of the burners are operated to full capacity, while the gas supply to other burners is shut off completely, Such operation makes for maximum efficiency at all times.

Figure illustrates a modified construction which is particularly useful where the furnace is to be operated a substantial part of the time at or near its maximum capacity. In the construction illustrated in Figure 5 the two paths of flow for the heated combustion products are maintained positively separated by a baiiie plate 40a which extends vertically upward from the pipe section 35 between the side walls El of each heat transfer section. It will be seen that by the provision of baille plates ii! and was in each heat transfer section the two paths of flow provided by the U-shaped baflle means ii are maintained substantially equal and entirely separated so that neither can rob the other to provide an uneven distribution of such heating combustion products.

I claim:

1. In a hot air heating furnace, a housing having a cold air inlet and a hot air outlet,

a series of heat transfer sections disposed in spaced side by side relationship within said housing, each of said sections being formed of spaced side walls defining an inner space for flow of hot gaseous products of combustion, a fiue conduit extending transversely through the upper portions of said heat transfer sections and communicating therewith through a downwardly facng op nin and an upwardly o ening U-shaped baflle in each heat transfer section facing the opening of said flue conduit to provide an indirect path for flow of combustion products thereto.

2. In a hot air heating furnace, a housing having a cold air inlet and a hot air outlet, a series of heat transfer sections disposed in spaced side by side relationship within said housing, each of said sections being formed of spaced side walls defining an inner space for flow of hot gaseous products of combustion, a flue conduit extending transversely through the upper portions of said heat transfer sections and communicating therewith through an opening in its lower side, an upwardly opening U-shaped baflle in each heat transfer section interposed between said flue conduit and the lower portions of said sections to provide an indirect path for flow of combustion products to said opening, and a vertical bafiie plate extending below the flue conduit to an intermediate portion of the U-shaped baflle.

3. In a hot air heating furnace, a housing having a cold air inlet and a hot air outlet, a heat transfer section mounted within said housing and formed of spaced side walls defining an inner space for flow of hot gaseous products of combustion, a fine conduit extending transversely through the upper portion of said section and communicating therewith through an opening in its lower side, an upwardly opening U-shaped baffle in said transverse section interposed between said flue conduit and the lower portion of said section to provide an indirect path for flow of combustion products to said opening, a vertical baffle plate extending below the flue conduit to an intermediate portion of the U-shaped baffle, and a second vertical bafile plate extending upwardly from the flue conduit and between said side walls to their junction.

4. In a hot air heating furnace, a housing having a cold air inlet and a hot air outlet, a heat transfer section disposed within said housing and formed of spaced side wallsdefining an inner space for flow of hot gaseous products of combustion, a flue conduit extending transversely through the upper portion of said section, replaceable means in said flue conduit providing an opening in its lower side, an upwardly opening U-shaped bafiie in said section interposed between said flue conduit and the lower portion of said section to provide an indirect path for flow of combustion products to said opening.

5. In a hot air heating furnace, a housing having a cold air inlet and a hot air outlet, a heat transfer section disposed within said housing and formed of spaced side Walls defining an inner space for flow of hot gaseous products of combustion, a flue conduit extending transversely through the upper portion of said section, replaceable means in said flue conduit providing an opening in its lower side, an upwardly opening U-shaped baflle in said section interposed between said flue conduit and the lower portion of said section to provide an indirect path for flow of combustion products to said opening, and a vertical baffle plate extending below the flue conduit to an intermediate portion of the U-shaped baffle. 6. In a hot air heating furnace, a housing having a cold air inlet and a hot air outlet, a heat transfer section disposed within said housing and formed of spaced side walls defining an inner space for flow of hot gaseous products of combustion, a flue conduit extending transversely through the upper portion of said section, replaceable means in said fluid conduit providing an openirr in its lower side, an upwardly opening U-shaped bafile in said section interposed between said flue conduit and the lower portion of said section to provide an indirect path for flow of combustion products to said opening, and vertical baflie'means extending below and above the flue conduit between said U-shaped battle and said walls to provide two separate paths of flow in the upper portion of said section to said opening.

7. In a hot air heating furnace, a housing havin a cold air inlet and a hot air outlet, a plurality of heat, transfer sections disposed within said housing and each formed of spaced side walls defining an inner space for flow of hot gaseous products of combustion, a flue conduit extending transversely through the upper portion of said sections, replaceable means in said flue conduit providing a bottom opening communicating with each of said sections, said opening being capable of variation by substitution of another like means having an opening of different size, a baffle in each of said sections interposed between said flue conduit and the lower portions of. said sections, there being passages of fixed size for flow of combustion products about said baffles, and a burner located in the lower portion of each of said heat transfer sections.

3. In a hot air heating furnace, a housing having a cold air inlet and a hot air outlet, a plurality of heat transfer sections disposed in spaced side by side relationship within said housing, each of said sections being formed of spaced sheet metal side walls defining an inner space for passage of hot gaseous products of combustion, a flue conduit extending transversely through the upper portions of said heat transfer sections and communicating therewith, and an upwardly opening U-shaped bafile in each heat transfer section below said flue conduit to provide an indirect path for flow of combustion products thereto, said bafiie being provided by complemental formed portions of said metal side walls.

9. In a hot air heating furnace, a housing having a cold air inlet and a hot air outlet, a plurality of heat transfer sections disposed in spaced side by side relationship within said housing, each of said sections being formed of spaced metal side walls defining an inner space for passage of hot gaseous products of combustion, and a box-like control chamber extendin generally at right angles to the planes of said sections, said sections having similar lower corners notched to receive a corner portion of said chamber, said chamber being connected to said respective side walls and in communication with said sections through the said notched corners.

10. In a hot air heating furnace, a housing having a cold air inlet and a hot air outlet, a plurality of heat transfer sections disposed in spaced side by side relationship within said housing, each of said sections being formed of spaced metal side walls defining an inner space for passage of hot gaseous products of combustion, and a boxlike control chamber extending generally at right angles to the planes of said sections, said sections having similar lower corners notched to receive a corner portion of said chamber and provide for communication between each of said sections and said chamber, said chamber being secured to said side walls and a wall of said housing to provide a supporting connection for said sections.

GEORGE A. TUCK. 

